Rose weevils, also referred to as Fuller rose weevils or rose beetles, infest a variety of host plants besides roses. Familiarize yourself with the appearance of rose weevils and the associated symptoms and damage caused by their presence. Then use an effective insecticide for rose weevil control in your home garden.
Before using an insecticide, confirm in your identification of these pests to ensure proper treatment. Both larval and adult rose weevils cause plant damage. Larvae are white with a yellow head, black mandibles and no legs, according to the University of Florida IFAS Extension. The adult weevils are a brown-gray hue with white specks and protruding eyes. Adult rose weevils measure approximately 1/3 inch long.
Search for insecticides for your particular host plant. What works on roses may not be well-suited for other plants. Host plants of the rose weevil generally include roses, beans, peaches, rhubarb, potatoes, strawberries and citrus, according to the University of Florida IFAS Extension. Though the list continues to include other host plants less often infested, verify that your plant is, indeed, infested with the rose weevil before applying an insecticide.
Larvae damage plants by chewing on root parts, according to the University of Florida IFAS Extension. Since damaged roots are left incapable of absorbing substantial water, plants experience nutrient deficiency and dehydration and often die. Adult rose weevils damage leaves and shoots. Look for small holes or chewed leaf borders; in extreme cases, rose weevils eat all leaf plant tissue except for the main vein. Damage is most easily prevented with use of an insecticide.
Chemicals for Foliage
For chemical control applied to foliage, use a petroleum-based insecticide to control adult populations and to prevent laid eggs from adhering to plant surfaces. For example, the University of Florida IFAS Extension suggests the use of an insecticide with the active ingredient diflubenzuron with a petroleum oil of 97 percent concentration up to three times every season.
Chemicals for Soil
Chemicals applied to the soil are referred to as chemical barriers. This type of insecticide treats larvae just after they hatch to keep them from destroying root systems, according to the University of Florida IFAS extension. For newly born rose weevil larvae, use an insecticide with the active ingredient bifenthrin applied from the base of the plant to moist soil free of plant debris. This soil barrier remains active in soil for approximately three weeks.